in the book it says that chapter squad based abilities only effect marines of that chapter yet many of these abilities are worded in such a way to suggest that they effect all battle brothers within range. Is it merely that these abilities only count as being centered on marines from said chapter?

You have to be of the same Chapter to benefit from or partake in Chapter Squad Mode Abilities. There are some loopholes around this restriction, though. In the main book, the Tactical Marine has an ability that can extend Chapter Squad Mode Abilities to other Space Marines. I've heard that there are some other ways around it in Rites of Battle, too.

what about an ultramarines ability to restore cohesion?

That's the exception case. It can be used to restore Cohesion, regardless of who else is in the squad. Great ability!

dean said:

This isn't an ability that grants any kind of benefit to a space marine. Yes, it benefits the cohesion restoration, but it does not target any kill-team member. This is a rare exeption to the case.